Monthly Archives: August 2014

NeedThis is a website where you can create lists. Those lists are saved server-side and you can share the link to your list with your friends. Entries have three attributes: Name, Link and Status (Not released, Available, Downloading and Completed).

I’ve written NeedThis in Node.js. The lists are stored in a NoSQL database and on the frontend runs Backbone.js MVC. There’s really not much code behind it, but I couldn’t find a similar service on the internet that fits my needs.

The syntax is very similar to Backbone, but of course without any dependencies. This code works best in a modern NodeJS environment where you do not need to support old JavaScript implementations. Bitbucket repository.

Beautiful right? This messy line of brackets, exclamation points and plus signs evaluates to the string “2014”. You can try it by pasting it into your browsers console or using Node.js.

Let’s have a closer look at the first part of it:

[!+[]+!+[]]

This produces an array with one entry: 2. If we break it down even further, it starts to make sense:

+!+[]

This code consists of four elements (differently colored). On the right we got a simple, empty array. The plus sign in front of it automatically casts it into a number, because that’s how loosely typed languages work. We can prove it by running this:

Number(new Array())

Alright, so casting an array into a number results in 0. The next element we need to look into is the exclamation point. The “!” operator inverts a boolean. But our 0 from above is not a boolean. No problem, JavaScript just casts it into one like we would expect it to do in “normal” code. We are now left with this:

!+[]

All we have to do now is simply cast true back into a number by using the plus operator:

+!+[]

Now if we chain two of those together, we get our first value of “2014”; “2”!

+!+[]+!+[]

And that’s the whole magic. The rest is pretty much the same, I won’t explain it all here. There is a site called JSFuck.com which can produce this kind of code. Quite interesting!

Introduction

I really like the MOBA League of Legends which is currently the most played game in the world. In LoL there are two teams of five people fighting on a big map in order to destroy the enemy nexus. After starting a game, many people will visit lolnexus.com during the loading screen, a site that provides live game details. You get insight into their ranking , runes and masteries which can possibly help you to win the game.

For my weekend project I wanted an application to do the following tasks for me:

Check if player “x” is in a game every 20 seconds

Start TV using CEC

Start a web browser and point it to lolnexus.com

Wait until game is over and turn off TV

Sounds simple right?

Turning a TV on using CEC

Consumer Electronics Control (CEC) is used to control a TV over the HDMI cable. I found a library called libCEC (Tutorial) that compiles on Raspbian. LibCEC installes the command line utility cec-client that I used in my application.

echo "on 0" | cec-client -s

Piping “on 0” into cec-client turns the TV on. You can use “standby 0” to turn it off. Now I need to find out how I can start a web browser on the Raspberry Pi.

Starting a browser in kiosk mode

Kiosk mode means starting it in fullscreen with no visible controls. I used the pre-installed browser Midori for this. But before you can start a browser, you need to start a graphical interface:

startx &

The “&” is used to start the process in background. “startx” should now have started a GUI on display :0. Now let’s start the browser:

midori -e Fullscreen --display :0 -a http://lolnexus.com/...

That’s it. Using this knowledge I created a simple application to turn my TV on whenever I started a new game and display lolnexus. Since I often get snacks during loading screen and have to walk past my TV, I can now simultaneously prepare myself for the game.